Chlorothiolformate pesticide



United States Patent 3,093,537 CHLOROTHIOLFORMATE PESTICIDE Harry Tilles, 703 Balra Drive, El Cerrito, Calif.

No Drawing. Original application Sept. 6, 1960, Ser. No. 53,924. Divided and this application Nov. 16, 1961, Ser. No. 158,632

8 Claims. (Cl. 167--22) This invention relates in general to a method for the preparation of chlorothiolformates and to the use thereof.

Various methods are known for the preparation of lower alkyl (C -C dodecyl and phenyl chlorothiolformates but each of these afford only relatively low yields and impure products. Further, certain known methods require a number of days for completion, require refrigerated cooling and large volumes of reaction mixture, do not afford uniform results (exhibiting sensitivity to reaction conditions) or require the preparation of lead mercaptides.

It is therefore an object of this invention to provide a method for the production of alkyl, lower cycloalkyl, alkenyl, aryl, aralkyl and alkaryl chlorothiolformates and substitution products thereof by a straight-forward method which yields a number of novel compounds. I

It is a further object of this invention to provide a method for the production of the aforementioned chlorothiolformates by a method which results in near quantitative yields. Still another object of this invention is to provide compounds for use in the control of nematodes and fungi and methods for using these compounds against such organisms.

Generally, this invention relates to a process wherein a mixture of the appropriate mercaptan and phosgene is brought into intimate contact with activated carbon which acts as a selective catalyst for the reaction.

II R-SH 0001, n-s-o-cn 1101 where R is alkyl, cycloalkyl, lower alkenyl, aryl, alkaryl, aralkyl, haloaryl, haloarylalkyl and carboalkoxyalkyl.

Similarly, phosgene and a dithiol are contacted in the presence of finely pulverized activated carbon which acts as a selective catalyst for the reaction HS(CHz)uSH 2000]: CMHJSGJHQHSPJOI 2HOl .Where n is 3-5.

The process can be carried out continuously by passing the mercaptan or dithiol and phosgene mixture through a bed of the carbon catalyst in a tubular reactor.

The selectivity of the catalyst is rather surprising. A by-product which is always formed when the known art procedures are used is the dithiolcarbonate which can be formed by either of two paths:

0 0 RS-(i01 RSH RS-i JSR H01 Similar equations may be written for the reaction involving the dithiol. As can be seen by the two above equations, an excess of mercaptan will favor the formation of dithiolcarbonate. It has been found that dithiolcarbonate is formed in considerable amounts using various of the known procedures, even when large excesses of phosgene are employed.

It is, therefore, the more surprising that we have de-. tected only traces of dithiolcarbonate in our methyl chlorothiolformate and ethyl chlorothiolformate, although in some of our reactions, large excesses of mercaptan were present. This indicates that the carbon catalyst catalyzes "ice the reaction of the phosgene and mercaptan to the chlorothiolformate but does not carry the reaction further.

Reaction conditions will vary depending upon the particular mercaptan used. it has been observed that the rate of formation of n-octyl chlorothiolformate is slower than the rate of formation of methyl and ethyl chlorothiolformates. Hence, a longer catalyst bed will be required to effect conversion of the octyl mercaptan.

The carbon may be activated in any of the conventional fashions as by heating with chlorine, steam, carbon dioxide or sulfuric acid.

It is also advised that the reaction temperatures be maintained as low as possible, consonant with reasonable reaction rates, since, at high temperatures, the disulfide begins to form in significant amounts. For example, for the methyl analogue, the maximum reaction temperature whereby to obtain a minimum of the disulfide is about 70 C. and for the ethyl analogue, this maximum lies within the range of 75 -l40 C.

As is known, the mercaptans exhibit varying reactivities and have varying decomposition temperatures and these must be taken into account in selecting optimum reaction temperatures.

In carrying out the process on a batch basis, the acti vated carbon, finely pulverized, is charged to the reactor with the mercaptan or dithiol. About 5-50% excess phosgene is then added, and cooling is applied if the r action is strongly exothermic. The mixture is then stirred for several hours, the excess phosgene stripped, the carbon filtered off, and the product worked up.

This activated carbon process has been found to be applicable for the preparation of unbranched lower and higher n-alkyl chlorothiolformates such as methyl, ethyl, n-propyl, n-butyl, n-amyl, n-hexyl, n-heptyl, n-octyl, ndecyl, n-dodecyl and n-tetradecyl chlorothiolformates; branched lower and higher n-alkyl chlorothiolformates such as isobutyl and 2-ethylhexyl chlorothiolformates; lower sec.-alkyl chlorothiolformates such as isopropyl and sec.-buty1 chlorothiolformates; aryl chlorothiolformates, such as phenyl, p-chlorophenyl, Z-naphthyl, o-tolyl, m-tolyl chlorothiolformates; aralkyl chlorothiolformates such as 'benzyl; p-chlorobenzyl and 2-phenylethyl chlorothiolformate; cycloaliphatic chlorothiolformates such as cyclohexyl chlorothiolfor mate; alkylene bis(chlorothiolformates) such as trimethylene, tetramethylene and pentamethylene chlorothiolformates; alkenyl chlorothiolformates such as allyl chlorothiolformate and carboalkoxyalkyl chlorothiolforrnates such as carboethoxymethyl chlorothiolformate.

Although with liquid mercaptans, it is preferable to use no solvent, a solvent can be used if it is desired, for example, to dissolve solid mercaptans.

It is unnecessary to use an excess of phosgene if it is more convenient to use an excess of mercaptan or dithiol. A satisfactory product can be obtained either way.

Examples are set forth below for purposes of illustration but these are not to be construed as imposing limitations on the scope of the invention other than as set forth in the appended claims.

Example 1 .M ethyl Chlorothiolformate A mixture of methyl mercaptan and phosgene was passed through a tubular glass reactor, 1" diameter x 24" long, containing 255 cc. (144 g.) of activated carbon, 4 x 10 mesh, at a rate of 24 g. (0.50 mole) per hour methyl mercaptan and 54.5 g. (0.55 mole) per hour phosgene for an interval of 65.8 hours. The reaction was cooled by a continuous flow of tap water through an external water jacket. The temperature of the reaction was 45 C. at a point /2" below the top of the catalyst bed, 25 C. at a point 3 /2 below the top of the catalyst bed, 16 C. at 6 /2" below the top and 13.5 C.

at 9 /2" from the top. The colorless liquid product was collected in a receiver at the bottom of the reactor. After the reaction was shut down, the product Was transferred to a l. flask and the volatile impurities were removed by bringing the mixture to reflux under water pump vacuum for 170 minutes, the pot temperature rising from 18- 26 C. Ice water was circulated through the condenser and a Dry Ice trap was inserted in series between the condenser and vacuum pump to recover any product that was stripped ofl. There was obtained as a residue 3746 g. (103% yield) of methyl chlorothiolforrnate, n 1.4839, (1 1.2761. Within experimental error, this is essentially :a quantitative yield. Gas-liquid chromatography shows this product to have a purity of 99.5

Analysis.Calcd. for C H ClOS: Cl, 32.07; S, 29.00. Found: Cl, 31.57; S, 28.59.

Example 2.Ethyl Chlorothiolformate A mixture of ethyl mercaptan and phosgene was passed through a tubular glass reactor, 1 diameter x 18" long, containing 150 cc. (61.9 g.) of activated carbon, x 50 mesh, at a rate of 31 g. (0.50 mole) per hour ethyl mercaptan and 54.5 g. (0.55 per mole) per hour phosgene for an interval of 1% hours. The reaction was cooled by a continuous flow of tap water through an external water jacket. The temperature of the reaction was 43.5- 465 C. at a point /2" below the top of the catalyst bed and 23.0-24.0 C. at a point 3%" below the top of the catalyst bed. The colorless liquid product was collected in a receiver at the bottom of the reactor. After the reaction was shut down, the product was transferred to a 500 cc. flask and the volatile impurities were removed by bringing the mixture to reflux under water pump vacuum for 32 minutes, the pot temperature rising from 435 C. Ice water was circulated through the condenser and a Dry Ice trap was inserted in series between the condenser and vacuum pump to recover any product that was stripped oil with the uncondensables. There was obtained as a residue 171 g. (91.5% yield) of ethyl chlorothiolformate, n 1.4777. Gas-liquid chromatography shows this product to have a purity of 98.9%.

Analysis-Calcd. for C H ClOS: Cl, 28.46; S, 25.74. Found: Cl, 27.96; S, 25.87.

Example 3.--n-Pr0pyl Chlorothiolformate A 4 neck 1 l. flask was provided with stirrer, thermometer, Dry Ice condenser and gas inlet tube. 20 g. of finely pulverized activated carbon and 228 g. (3.00 moles) of n-propyl mercaptan were charged to the flask. 312 g. (3.15 moles) of phosgene was then added over an interval of 31 minutes, maintaining the temperature between 20-32 C. The mixture was then allowed to stir for 170 minutes at 1926 C. Most of the excess phosgene was then stripped out with air and the mixture was then filtered with Dicalite Filter Aid. The filtrate was then transferred to a 1 l. flask and the volatile impurities were removed by refluxing under water pump vacuum for 20 minutes, the pot temperature rising from 2044 C. Tap water was circulated through the condenser and a Dry Ice trap was connected in series between the condenser and vacuum pump to recover any stripped-off product. There was obtained as a residue 397 g. (94.5% yield) of n-propyl chlorothiolformate, 11 1.4753, d 1.1341. Gas-liquid chromatography shows this product to have a purity of 98.9%.

Analysis.-Calcd. for C H ClOS: Cl, 25.58; S, 23.13. Found: Cl, 25.31; S, 23.36.

Example 4.i-Pr0pyl Chlorothiolformate A 4 neck 500 cc. flask was provided with stirrer, thermometer, Dry Ice condenser and gas inlet tube. 20 g. of finely pulverized activated carbon and 76 g. (1.00 mole) of i-propyl mercaptan were charged to the flask. 129 g. 1.30 moles) of phosgene was then added over an interval of 21 minutes, maintaining the temperature between 13 and 27 C. The mixture was then allowed to stir for 4 /2 hours at 11.523 C. The excess phosgene was then stripped OE With air and the mixture was filtered with Dicalite Filter Aid. The filter cake was washed with four 25 cc. portions of n-pentane. The combined filtrate was then refluxed under water-pump vacuum to remove volatile impurities and n-pentane. A Dry Ice trap was connected in series with the condenser and water pump to recover any product that was stripped off. There was obtained as a residue 123.1 g. (89.0% yield) of ipropyl chlorothiolformate, n 1.4704. Gas-liquid chromatography shows this product to have a purity of 98.0%.

Analysis.C-alcd. for C H ClOS: Cl, 25.58; S, 23.13. Found: Cl, 25.00; S, 22.59.

Example 5.n-Bulyl Clzlorothiolformate Into the same apparatus used in Example 3 was charged 30 g. of finely pulverized activated carbon and 270 g. (3.00 moles) of n-butyl mercaptan. 312 g. (3.15 moles) of phosgene was then added over an interval of 32 minutes, maintaining the temperature 'between 4-22" C. The mixture was then allowed to stir for 4 hours 23 minutes at 2227 C. The product was then worked up in a similar manner to Example 3. There was obtained as a residue 409 g. (89.5% yield) of n-butyl chlorothiolformate, 12 1.4736, (1 1.0980. Gas-liquid chromatography shows this product to have a purity of 98.5%.

Analysis.-Calcd. for C H ClOS: Cl, 23.23; S, 21.01. Found: Cl, 22.99; S, 21.03.

Example 6.Scc-Butyl Chlorot/ziolformate Into the same apparatus used in Example 4 was charged 20 g. of finely pulverized activated carbon and g. (1.00 mole) of sec-butyl mercaptan. 119 g. (1.20 moles) of phosgene was then added over an interval of 10 minutes, maintaining the temperature between 19.533 C. The mixture was then allowed to stir for 5 hours at 15.5 24.5 C. The excess phosgene was then stripped off with air and the mixture was filtered with Dicalite Filter Aid. The filter cake was Washed with four 25 cc. portions of n-pentane and the combined filtrate was concentrated on the steam bath. The residual liquid was then fractionally distilled under reduced pressure. There was obtained 117 g. (76.6% yield) of sec-butyl chlorothiolformate, B.P. (60 mm.) 89.590.0 C., n 1.4726.

Analysis.-Calcd. for C H ClOS: Cl, 23.23; S, 21.01. Found: Cl, 23.02; S, 21.45.

Example 7.i-Butyl Chlorothiolformate A 4 neck cc. flask was provided with stirrer, thermometer, Dry Ice condenser and gas inlet tube. 5 g. of finely pulverized activated carbon and 27.0 g. (0.30 mole) of isobutyl mercaptan were charged to the flask. 45 g. (0.45 mole) of phosgene was then added over an interval of 17 minutes, maintaining the temperature between 14- 27 C. The mixture was then allowed to stir for 4 hours 51 minutes at 14-26 C. The excess phosgene was then removed by stripping with air and the mixture was then filtered with Dicalite Filter Aid. The filter cake was washed with four 25-cc. portions of n-pentane and the combined filtrate was concentrated on the steam bath. The residual liquid Was fractionally distilled under reduced pressure. There was obtained 32 g. (69.8% yield) of isobutyl chlorothiolformate, .B.P. (10 mm.) 50.5-51.5 C., n 1.4720.

Analysis.--Calcd. for C H 'ClOS: Cl, 23.23; S, 21.01. Found: CI, 23.3; S, 21.0.

Example 8.n-Amyl Chlorothiolformate Into the same apparatus used in Example 4 was charged 20 g. of finely pulverized activated carbon and 104 g. (1.00 mole) of n-amyl mercaptan. 119 g. (1.20 moles) of phosgene was then added over an interval of 10 minutes, maintaining the temperature between 7-20.5 C.

The mixture was then'allowed to stir for 2 hour-s 47 minutes at 14.520.0 C. The mixture was then worked up .in the same manner as in Example 4. There was ob tained as a residue 149.4 g. (89.7% yield) of n-amyl chlorothiolformate, 11 1.4730 (d 1.0697). Gas-liquid chromatography shows this product'to have a purity of 97.4%. i

Analysis.Calcd. for C H 'C1OS: Cl, 21.27; S, 19.24. Found: Cl, 21.31; S, 19.51.

Example 9.n.- Hexyl Chlorothiolformate formate, B.P. (10 mm.) 93-96 C., r 1.4720, r2

Analysis.-Calcd. for CqHmclOS: Cl, 19.62; S, 17.74. Found: Cl, 19.9; S, 18.0.

Example 10.-n-Heptyl Chlorothiolformate Into the same apparatus used in Example 4 was charged 20 g. of finely pulverized activated carbon and 132 g. (1.00 mole) of n-heptyl mercaptan. 119 g. (1.20 moles) of phosgene was then added over an interval of 12 minutes, maintaining the temperature between 1622 C. The mixture was then allowed to stir for 3 hours and 8 minutes at 17.527 C. The mixture was then worked up in the same manner as in Example 6. There was obtained 152 g. (78.3% yield) of n-heptyl chlorotln'olformate, B.P. (10 mm.) 110-l12 C., n 1.4718, (1 1.0278.

Analysis.Calcd. for Cd-1 C108: Cl, 18.21; S, 16.47. Found: Cl, 18.2; S, 16.3.

Example 11a.-n-Octyl Chlorothzolformate Into the same apparatus used in Example 4 was charged 20 g. of finely pulverized activated carbon and 146 g. (1.00 mole) of n-octyl mercaptan. 119 g. (1.20 moles) of phosgene was then added over an interval of 17 minutes, maintaining the temperature between 9.518.5 C. The mixture was then allowed to stir for 5 hours 11 minutes at 17.5-28.5 -C. The mixture was then worked up in the same manner as in Example 6. There was obtained 181.5 g. (87.0% yield) of n-octyl chlorothiolformate, B.P. mm.) 124.0-124.5 C., n 1.4713, d 1.0148.

Analysis.-Calcd. for C H CIOS: C1, 16.98; S, 15.36. Found: Cl, 17.1; S, 15.7.

Example 11b.n-0ctyl Chlorothiolformate Into the same continuous reactor described in Example 2 and containing the same type and amount of catalyst was fed 73 g. (0.50 mole) per hour n-octyl mercaptan and 60 g. (0.60 mole) per hour phosgene for an interval of 2 hours. The reaction was cooled by a continuous flow of tap water through an external water jacket. The temperature of the reaction was 47-43 C. at a point /2" below the top of the catalyst bed and 2324.5 C. at a point 3 /2 below the top of the catalyst bed. The colorless liquid product was collected in a receiver at the bottom of the reactor. After the reaction was shut down, the pro-duct was heated on the steam bath with air to remove most of the volatiles and the residual liquid was then fractionally distilled under reduced pressure. There was obtained 189' g. (90.4%) yield of n-octyl chlorothiolformate, B.P. (10 mm.) 124.0-124.1, 11 1.4717.

Analysis.--Calcd. for C H CIOS: Cl, 16.98; S, 15.36. Found: Cl, 17.02; S, 15.26.

move any volatiles.

Example 12.n-Decyl Chlorothiolformate Into the same apparatus used in Example 4 was charged 20 g. of finely pulverized activated carbon and 176 g. 1.00 mole) otnadecyl mercaptan. 129 g. (1.30 moles) of phosgene was then added over an interval of 18 minutes, maintaining the temperature between 11-28 C. The mixture was then allowed to stir for 3 hours 24 minutes at 21-28 C. The mixture was then filtered with Dicalite Filter Aid and the filter cake was washed with four 25 cc. portions of npentane. The combined filtrate was concentrated on the steam bath and then transferred to al 1. round bottomed flask. This flask was attached to a 'Rinco Rotating Evaporator and heated with three infra-red lamps at 150 microns tor a short while to re- T-here remained behind as a liquid residue, 210.7 g. (89.1% yield) of n'decyl chlorothiolrformate, 11 1.4708, 01 09862.

Analysis.--Calcd. for C H ClOS:.C1,14.97; S, 13.54. Found: Cl, 14.70; S, 13.29.

Example 13.-n D0decyl Chlorothiolflormat e Into the same apparatus used in Example 4 was charged 20 g. of finely pulverized activated carbon and 104 g. (0.51 mole) of n-dodecyl mercaptan. 61 g. (0.61 mole) of phosgene was then added over an interval of 15 minutes, maintaining the temperature at 83l C. The mixture was then allowed to stir for 2 hrs. 48 minutes at 21- 27.5 C. 'It was then worked up in the same manner as in Example 12. There remained behind as a liquid residue 129 g. (95.5% yield) of n-dodecyl chlorothiol- -formate, n 1.4700.

Analysis.Calcd. for *C H ClOS: Cl, 13.39; S, 12.11. Found: Cl, 13.47; S, 12.00.

Example 14.-n-Tetradecyl Chlorothiolformate Into the same apparatus used in Example 7 was charged 5 g. of finely pulverized activated carbon and 46.1 g. (0.20 mole) of n-tetradecyl mercaptan. 24 g. (0.24 mole) of phosgene was then added over an interval of 42 minutes,

maintaining the temperature at 25-54 C. The mixture was then allowed to stirfor 4 hours 26 minutes at 254- 56 C. It was then worked up in the same manner as in Example 12. There remained behind as a liquid residue 53.1 g. (90.5% yield) of n-tetradecyl chlorothiolformate,

Analysis.Calcd. for C H ClOS: Cl, 12.10; S, 10.95.

Found: Cl, 11.10; S, 10.73.

IR spectra confirms the structure of this product.

Example 15.Phenyl Chlorothiolf ormate Into the same apparatus used in Example 4 was charged '30 g. of finely pulverized activated carbon and 110 g.

(1.00 mole) of thiophenol. 119 g. (1.20 moles) of phosgene was then added over an interval of 7 minutes, maintaining the temperature at 519- C. The mixture was then allowed to stir for 3 hours 17 minutes at 15.550.0 C. The mixture was then filtered with Dicalite Filter Aid and the cake was washed with four 25 cc. portions Example 1l6.-0-Tolyl Chlorothiolformate mole) of o-toluenethiol and cc. of n-pentane solvent.

21 g. (0.21 mole) of phosgene was then added over an interval of 7 minutes, maintaining the temperature at 17.5-27.0 C. The mixture was then allowed to stir for 6 hours 20 minutes at 27-35 C. It was then worked up in the same manner as in Example 7. There was obtained 18.4 g. (70.5% yield) of o-tolyl chlorothiolformate, B.P. (10 mm.) 111-112 C., 11 1.5750.

Analysis.-Calcd. for C H ClOS: Cl, 18.99; S, 17.18. Found: Cl, 18.91; S, 17.13.

Example 17.m-Tolyl Chlorothiolformate Into the same apparatus used in Example 7 was charged 5 g. of finely pulverized activated carbon and 37.2 g. (0.30 mole) of m-toluenethiol. 39 g. (0.39 mole) of phosgene was then added over an interval of 45 minutes, maintaining the temperature at 16-40.5 C. The mixture was then allowed to stir for 2 hours 34 minutes at 16-30" C. It was then worked up in the same manner as in Example 7. There was obtained 31.2 g. (55.8% yield) of m-tolyl chlorothiolforma-te, B.P. (10 mm.) 115.5-116.0 C., 21 1.5701.

Analysis.-Calcd. for C H ClOS: Cl, 18.99; S, 17.18. Found: Cl, 19.05; S, 17.20.

Example 18.p-T0lyl Chlorotlziolformate Into the same apparatus used in Example 7 was charged 5 g. of finely pulverized activated carbon, 37.2 g. (0.30 mole) of p-toluenethiol and 150 cc. of n-pentane solvent. 45 g. (0.45 mole) of phosgene was then added over an interval of 6 minutes, maintaining the temperature at 19.5- 295 C. The mixture was then allowed to stir for 1 hour 24 minutes at 20-27 C. It was then Worked up in the same manner as in Example 7. There was obtained 12.2 g. of unreacted p-toluenethiol and 25.5 g. (67.8% yield based on recovered p-toluenethiol) of p-tolyl chlorothiolformate, B.P. (10 mm.) 114.0-117.5 C., n 1.5725.

Analysis.-Calcd. for C H- CIOS: Cl, 18.99; S, 17.18. Found: Cl, 19.00; S, 16.81.

Example 19.[I-Clzlr0phenyl Chlorotlziolformate Into the same apparatus used in Example 4 was charged 20 g. of finely pulverized activated carbon and 144.5 g. (1.00 mole) of p-chlorothiophenol. The p-chlorothiophenol was then heated to 60 C. until it was all melted and then 119 g. (1.20 mole) of phosgene was added over an interval of 1 hour 26 minutes at 38-56 C. The mixture was then allowed to stir for 3 hours and 34 minutes at 38-61 C. It was then worked up in the same manner as in Example 6. There was obtained 179 g. (86.5% yield) of p-chlorophenyl chlorothiolformate, B.P. (10 mm.) 126.0-126.5 C., n 1.5961.

Analysis.Calcd. for C H Cl OS: Cl, 34.24; S, 15.48. Foundz'Cl, 34.25; S, 15.35.

Example 20.2-Naphthyl Chlorothiolformate Into the same apparatus used in Example 7 was charged g. of finely pulverized activated carbon, 24 g. (0.15 mole) of 2-naphthalenethiol and 100 cc. of tetrahydrofuran solvent. 19 g. (0.20 mole) of phosgene was then added over an interval of 7 minutes at 19.5-39.5 C. The mixture was then allowed to stir for 1 hour 54 minutes at 36.5-59.5 C. It was then filtered with Dicalite Filter Aid and the filtrate was concentrated on the steam bath. The crude solid product was dissolved in 500 cc. of npentane and washed with two 100 cc. portions of aqueous sodium hydroxide solution. A considerable amount of solid formed, which was insoluble in both pentane and water. It appeared as if the caustic wash caused decomposition. The mixture was then filtered and the pentane filtrate was concentrated on the steam bath. There was obtained 12.2 g. (36.6% yield) of Z-naphthyl chlorothiolformate, M.P. 49-51 C.

Analysis.Calcd. for C H CIOS: Cl, 15.92; S, 14.40. Found: Cl, 15.89; S, 14.15.

Example 21.Benzyl Chlorothiolformate Into the same apparatus used in Example 7 was charged 5 g. of finely pulverized activated carbon and 37.2 g.

(0.30 mole) of benzyl mercaptan. 45 g. (0.45 mole) of phosgene was then added over an interval of 17 minutes, maintaining the temperature at 12-25 C. The mixture was then allowed to stir for 5 hours and 54 minutes at 12- 24.5 C. It was then worked up in the same manner as in Example 12. There was obtained as a liquid residue, 50.0 g. (89.4% yield) of benzyl chlorothiolformate, 11 1.5703.

Analysis.-Calcd. for C H ClOS: Cl, 18.99; S, 17.18. Found: Cl, 19.37; S, 16.39.

IR spectra confirms the structure of this product.

Example 22.p-Chlorobenzyl Chlorothiolformate Into the same apparatus used in Example 7 was charged 5 g. of finely pulverized activated carbon and 47.5 g. (0.30 mole) of p-chlorobenzyl mercaptan. 36 g. (0.36

mole) of phosgene was then added over an interval of 47 minutes, maintaining the temperature at 42.5-57.0 C. The mixture was then allowed to stir for 3 hours 46 minutes at 42.5-59.0 C. It was then worked up in the same manner as in Example 12. There was obtained as a liquid residue 61.2 g. (92.3% yield) of p-chlorobenzyl chlorothiolformate, n 1.5845.

Analysis.-Calcd. for C H Cl OS: Cl, 32.07; S, 14.50. Found: Cl, 31.80; S, 14.11.

Example 23.2-Phenylethyl Clzlorozhiolformate Example 24.-Cyclohexyl Clzlorotlziolformale Into the same apparatus used in Example 7 was charged 5 g. of finely pulverized activated carbon and 23.2 g. (0.20 mole) of cyclohexyl mercaptan. 30 g. (0.30 mole) of phosgene was then added over an interval of 12 minutes, maintaining the temperature at 12-20 C. The mixture was then allowed to stir for 3 hours 38 minutes at 1626 C. It was then worked up in the same manner as Example 7. There was obtained 25.6 g. (71.7% yield) of cyclohexyl chlorothiolformate, B.P. (10 mm.) 96.0-97.0 C., 11 1.5109.

Analysis.Calcd. for C H ClOS: Cl, 19.84; S, 17.94. Found: Cl, 19.84; S, 17.93.

Example 25 .Trimethylene Bis(Chlorothiolformate) Into the same apparatus used in Example 7 was charged 5 g. of finely pulverized activated carbon and 21.6 g. (0.20 mole) of 1,3-propanedithiol. 60 g. (0.60 mole) of 'phosgene was then added over an interval of 36 minutes at a temperature of 8-28 C. The mixture was then allowed to stir for 4 hours 58 minutes at 8-16 C. It was then worked up in the same manner as in Example 12. There remained behind as a liquid residue 33.2 g. (71.3% yield) of trimethylene bis(chlorothiolformate), 11 1.5512.

Analysis.Calcd. for C5H Cl202SgZ Cl, 30.41; S, 27.50. Found: Cl, 30.41; S, 27.12.

Example 26.Telramethylene Bis(Chlorothiolformate) Into the same apparatus used in Example 7 was charged 5 g. of finely pulverized activated carbon and 24.4 g. (0.20 mole) of tetramethylene dimercaptan. 60 g. (0.60 mole) of phosgene was then added over an interval of 37 minutes, maintaining the temperature at 8.525 C. The mixture was then allowed to stir for 4 hours 24 minutes at 8.5-l3.0 C. It was then worked 9 up in the same manner as in Example 12. There remained behind a solid residue which was triturated with three 100 cc. portions of n-pentane and then dried. There was obtained 42.9 g. (86.9% yield) of tetramethylene bis(chlorothiolformate), M.P. 43.5-46.0 C.

Analysis.Calcd. for C H Cl O S Cl, 28.69; S, 25.94. Found: CI, 28.6; S, 25.5.

Example 27.-Pentamethylene Bis(Chlr0thiolformate) Into the same apparatus used in Example 7 was charged g. of finely pulverized activated carbon and 27.2 g. (0.20 mole) of 1,5-pentanedithiol. 60 g. (0.60 mole) of phosgene was then added over an interval of 14 minutes, maintaining the temperature at 14.527.0 C. The mixture was then allowed to stir for 5 hours 41 minutes at 1422 C. It was then worked up in the same manner as in Example 12. There remained behind as .a liquid residue, 47.7 g. (91.1% yield) of pentamethylene bis(chlorothiolforrnate), 11 1.5374.

Analysis.Calcd. for C H C1 O S Cl, 27.07; S, 24.48. Found: Cl, 27.02; S, 24.53.

Example 28.Allyl Chlorothiolformate Into the same apparatus used in Example 7 was charged 5 g. of finely pulverized activated carbon and Example 29.Carb0eth0xymethyl Chlorothiolformate Into the same apparatus used in Example 7 was charged 5 g. of finely pulverized activated carbon and 36 g. (0.30 mole) of ethyl mercaptoacetate. 45 g. (0.45 mole) of phosgene was then added over an interval of 19 minutes, maintaining the temperature at 1521 C. The mixture was then allowed to stir for 3 hours 44 minutes at 1521.5 C. It was then worked up in the same manner as in Example 7. There was obtained 17.3 g. of unreacted ethyl mercaptoacetate and 16.1 g. (56.7% yield based on recovered ethyl mercaptoacetate) of carboethoxymethyl chlorothiolformate, B.P. mm.) 99.5-100.0 C., 11 1.4786.

Analysis.Calcd. for C5H7CIO3SZ Cl, 19.41; S, 17.56. Found: C1, 19.48; S, 17.4.

Example 30.2-Ethylhexyl Chlorothiolformate Into the same apparatus used in Example 7 was charged 5 g. of finely pulverized activated carbon and 43.8 g. (0.30 mole) of Z-ethylhexyl mercaptan. 36 g. (0.36 mole) of phosgene was then added over an interval .of 1 hr. 22 min., maintaining the temperature at 50- 55 C. The mixture was then allowed to stir for 4 hrs. 6 min. at 24-60" C. It was then worked up in the same .manner as in Example 7. There was obtained 39.5 g.

(63.1% yield) of 2-ethylhexyl chlorothiolformate, B.P. (10 mm.) 112.5-113.5 C., 11 1.4750.

Analysis.Calcd. for C H CIOS: Cl, 16.98; S, 15.36. Found: Cl, 16.86; S, 15.36.

Example 31.--t-Butyl Chlorothiolformate C. for 20.5 hours. The excess phosgene was then removed by stripping with air. The mixture was then filtered with Dicalite Filter Aid. The filter cake was washed with a 125 cc. portion of n-pentane and the combined filtrate was transferred to a 500 cc. still pot and the volatiles were removed by distilling through a fractional distillation column under reduced pressure while not allowing the distillant in the still pot to rise above 60 C. There was obtained as a residue 197 g. (64.6% yield) of tertiary butyl chlorothiolformate, 11 1.4694.

Analysis.Calcd. for C H ClOS: Cl, 23.23; S, 21.01. Found: C1, 22.96; S, 20.78.

Various of the compounds are efiective as fnmigants against A. niger, nematodes, F. solwni, and R. solani, as mildew eradicants, as herbicides against squash and soybeans, as agents for the control of rust, as pesticides against mites and housefiies. Where the compounds exhibit relatively low activity against various pests, bacteria and plants they may be reacted with various amines to form thiolcarbamates which are useful as pre-emergence herbicides.

Further details regarding the use of these compounds are set forth below.

(1) Methyl chlorothiolformate:

Fumigant control of A. nigger-100% Nematodes 110 p.p.m.)-100% control, no phytotoxicity F. solani (55 p.p.m.)-100% control, no phytotoxicity R. solani (55 p.p.m.)75% control, no phytotoxicity (2) Ethyl chlorothiolformate:

Fumigant control of A. niger--% Nematodes (110 p.p.m.)75% control, no phytotoxicity F. solani (110 p.p.m.)75% control, no phytotoxicity (3) n-Propyl chlorothiolformate:

Nematodes (110 p.p.m.)% control, no phytotoxicity F. s0la1ni75% control, no phytotoxicity (4) i-Propyl chlorothiolformate:

When this compound is reacted with di-n-propylamine it forms isopropyl di-n-propylthiolcarbamate which is a pre-emergence herbicide that prevents the germination of oat seeds at 20 lbs/acre in a can test.

(5) n-Butyl chlorothiolformate:

Fumigant control of A. niger-90% Nematodes p.p.m.)100% control, no phytotoxicity F. solam (27 p.p.m.)-100% control, no phytotoxicity (6) sec-Butyl chlorothiolformate:

When this compound is reacted with di-n-propylamine it forms sec-butyl di-n-propylthiol-carbamate which is a pre-emergence herbicide that completely controls the germination of oat and rye seeds at 2% lbs./ acre in a flat test.

(7) i-Butyl chlorothiolformate:

F. solani (27 p.p.m.)--100% control, no phytotoxicity (8) n-Amyl chlorothiolformate:

Fumigant control of A. niger100% Nematodes (110 p.p.m.)--100% control, no phytotoxicity F. solani (27 p.p.m.)-100% control, no phytotoxicity (9) n-Hexyl chlorothiolformate:

Fumigant control of A. niger 100% F. solani (110 p.p.m.)-100% control, no phytotoxicity (10) n-Heptyl chlorothiolformate:

Fumigant control of A. niger--100% 1 1 (11) n-Octyl chlorothiolformate:

Fumigant control of A. niger-100% F. solani (110 p.p.m.)100% control, no phytotoxicity (12) n-Decyl chlorothiolformate:

Completely kills squash and soybeans when sprayed on the young seedlings at 0.2% concn.

50-75% control of mildew at 1000 p.p.m.

(l3) n-Dodecyl chlorothiolformate:

Completely kills squash when sprayed on the young seedlings at 0.2% concn. and severely injures soybeans.

75100% control of mildew at 500 p.p.m.

(14) n-Tetradecyl chlorothiolformate:

Mites, post embryonic, 0.l2%100% control Completely kills squash when sprayed on young seedlings at 0.2% concn.

75100% control of rust and mildew at 1000 p.p.m.

(15) Phenyl chlorothiolformate:

When reacted with dimethylamine it forms phenyl dimethylthiolcarbamate which completely prevents germination of rye at 10 lbs./ acre.

(16) o-Tolyl chlorothiolformate:

Fumigant control of A. niger100% F. solani (27 p.p.m.)l% control, no phytotoxicity Kills squash seedlings at 0.2% concn.

(17) m-Tolyl chlorothiolformate:

Fumigant control of A. niger100% F. solani (27 p.p.m.)100% control, no phytotoxicity 18) p-Tolyl chlorothiolformate:

Fumigant control of A. niger100% F. solani (27 p.p.m.)l00% control, no phytotoxv icity R. solani (27 p.p.m.)75% control, no phytotoxicity Kills soybean seedlings at 0.2% concn.

(19) p-Chlorophenyl chlorothiolformate:

Fumigant control of A. niger-100% F. solani (27 p.p.m.)100% control, no phytotoxicity 100% kill of M. domestica insect at 0.5% concn.

(20) Z-naphthyl chlorothiolformate:

F. solani (110 p.p.m.)--100% control, no phytotoxicity Kills soybean seedlings at 0.2% concn.

(21) Benzyl chlorothiolformate:

F. solani (27 p.p.m.)100% control, no phytotoxicity 100% kill of M. domestica insect at 0.5 concn.

75-100% control of nematodes at 110 p.p.m.

75% control of R. solani at 110 p.p.m.

(22) p-Chlorobenzyl chlorothiolformate:

100% kill of M. domestica insect at 0.5% concn.

F. solani (55 p.p.m.)100% control, no phytotoxicity R. solani (110 p.p.m.)75% control, no phytotoxicity Rate/acre Ge Growth 40 lb. 20 0+ lb. 60 0+ (25) Trimethylene bis(chlorothiolformate):

Fumigant control of A. niger1()0% 100% kill of M. domestica insect at 0.5 concn. Nematodes (110 p.p.m.)l00% control, no phytotoxicity F. solani (110 p.p.m.)% control, no phytotoxicity (26) Tetrarnethylene rbis(chlorothiolformate):

Fumigant control of A. niger-100% 100% kill of M. domestica insect at 0.5 concn.

Nematodes p.p.m.)100% control, no phytotoxicity F. solani (110 p.p.m.)100% control, no phytotoxicity (27) Pentamethylene bis(chlorothiolformate) 100% kill of M. domestica insect at 0.5 concn.

F. solani (110 p.p.m.)100% control, no phytotoxicity 100% post embryonic control of mites at 0.12%

Kills squash seedlings at 0.2% concn.

(28) Allyl chlorothiolformate:

Nematodes (110 p.p.m.)100% control, no phytotoxicity F. solani (27 p.p.m.)l00% control, no phytotoxicity (29) Carboethoxymethyl chlorothiolformate:

Fumigant control of A. niger-100% F. solani (27 p.p.m.)l00% control, no phytotoxicity R. solani (110 p.p.m.)75% control, no phytotoxicity (30) Z-ethylhexyl chlorothiolformate:

Fumigant control of A. niger100% (3 l) t-Butyl-chlorothiolformate:

When reacted with di-n-propylamine this compound yields S-tert. butyl di n propylthiolcarbamate which when applied at the rate of 5 lbs./ acre prevents germination and growth of nut grass and oats. At this rate, it also kills foxtail and is almost completely effective for the prevention of germination thereof.

Tests .of the compounds, as outlined above, indicate that they are most useful in the control of nematodes and fungi. The compounds may be formulated with any suitable common solvent such as diesel oil or paint thinner. In use, they should be diluted to an extent which enables them to be applied uniformly by means of available farm equipment. The compounds may also be formulated as emulsible concentrates as by the use of such emulsifiers as the polyoxyalkylene derivatives of hexitol anhydride partial long chain fatty acid esters which enable them to be dispersed in water and applied as dilute aqueous emulsions. An effective dosage varies between 13 p.p.m. 51nd 110 p.p.m. of soil when used against nematodes and ungi.

A method for reacting these compounds with amines to form thiolcarbamates is as follows:

One mole of the chlorothiolformate is added gradually with cooling (e.g. in an ice bath) to 2.1 moles of the appropriate amine in an ether solvent. The mixture is allowed to stand for five minutes and the precipitated amine hydrochloride is removed by washing with water. The ether solution is then washed with dilute hydrochloric acid (e.g. 5 M) to remove any unreacted amine and this is followed by washing with several portions of water. The ether solution is dried over MgSO filtered and the ether evaporated off on steam bath. The product may be distilled for purification purposes, if desired.

Obviously, many modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof and, therefore, only such limitations should be imposed as are indicated in the appending claims.

This application is a division of copending application Serial No. 53,924, filed September 6, 1960.

I claim:

1. A method of controlling nematodes and fungi comprising: applying thereto a small amount of a compound 13 selected from the class consisting of compounds of the general formula where R is selected from the class consisting of alkyl, cycloalkyl, lower alkenyl, aryl, alkaryl, aralkyl, haloalkyl, haloaralkyl, carboalkoxyalkyl and Cl SR'SOOl wherein R is a polymethylene group.

2. The method of claim 1 wherein the said compound is methyl chlorothiolformate.

3. The method of claim 1 wherein the said compound 1 is ethyl chlorothiolformate.

10 is benzyl chlorothiolformate.

References Cited in the file of this patent UNITED STATES PATENTS 2,282,732 Lean May 12, 1942 2,955,977 Warner Oct. 11, 1960 2,966,522 Webb Dec. 27, 196) 

1. A METHOD OF CONTROLLING NEMATODES AND FUNGI COMPRISING: APPLYING THERETO A SMALL AMOUNT OF A COMPOUND SELECTED FROM THE CLASS CONSISTING OF COMPOUNDS OF THE GENERAL FORMULA 